Redox-active covalent organic polymers(COPs)have emerged as appealing renewable electrode materials for next-generation Li-ion batteries,but their performance is limited by insufficient redox sites and inadequate Li-i...Redox-active covalent organic polymers(COPs)have emerged as appealing renewable electrode materials for next-generation Li-ion batteries,but their performance is limited by insufficient redox sites and inadequate Li-ion diffusion.Here,we develop a novel class of mesoporous covalent organic polymer(namely TF-Azo-COP)bearing multiple redox sites and explore its first use as efficient 18-electron-redox anodes for superior Li-ion storage in both coin-type and fiber-type batteries.The newly produced TF-Azo-COP involves three types of active sites including C=N in triazines and imines,N=N in azo,and C6-ring aromatics to enable 18-Li-ion storage on one repeatable segment,while affording extendedπ-conjugation for fast electron transfer and a pore size of~2.5 nm for facilitated ion diffusion with a high coefficient up to~10^(-10)cm^(2)s^(-1)—superior to some reported organic electrodes.Meriting from the above,pairing TF-Azo-COP with metal Li endows a coin cell with good cycling stability and a large reversible capacity of 795.4 mAh g^(-1)at 0.1 A g^(-1)—representing one of the best performances among reported organic electrodes.When coupled with fiber-shaped LiFePO_(4)cathodes,the assembled fiber cell delivers an excellent combination of linear capacity(0.23 mAh cm^(-1)),energy density(0.55 mWh cm^(-1)),cycling stability(250 cycles),and good flexibility.展开更多
The pseudo-two-dimensional(P2D)model plays an important role in exploring physicochemical mechanisms,predicting the state of health,and improving the fast charge capability for Li-ion batteries(LIBs).However,the fast ...The pseudo-two-dimensional(P2D)model plays an important role in exploring physicochemical mechanisms,predicting the state of health,and improving the fast charge capability for Li-ion batteries(LIBs).However,the fast charge leads to the lithium concentration gradient in the solid and electrolyte phases and the non-uniform electrochemical reaction at the solid/electrolyte interface.In order to decouple charge transfer reactions in LIBs under dynamic conditions,understanding the spatio-temporal resolution of the P2D model is urgently required.Till now,the study of this aspect is still insufficient.This work studies the spatio-temporal resolution for dynamic/static electrochemical impedance spectroscopy(DEIS/SEIS)on multiple scales.In detail,DEIS and SEIS with spatio-temporal resolutions are used to decouple charge transfer reactions in LIBs based on the numerical solution of the P2D model in the frequency domain.The calculated results indicate that decoupling solid diffusion requires a high spatial resolution along the r-direction in particles,decoupling electrolyte diffusion and interfacial transfer reaction requires a high spatial resolution along the x-direction,and decoupling charge transfer reactions in LIBs at an extremely low state of charge(SOC)requires an extremely high temporal resolution along the t-direction.Finally,the optimal range of spatio-temporal resolutions for DEIS/SEIS is derived,and the method to decouple charge transfer reactions with spatio-temporal resolutions is developed.展开更多
The rapid accumulation of spent LiFePO_(4)(LFP)cathodes from retired lithium-ion batteries necessitates the development of effective and environmental-friendly recycling strategies.In this context,direct regeneration ...The rapid accumulation of spent LiFePO_(4)(LFP)cathodes from retired lithium-ion batteries necessitates the development of effective and environmental-friendly recycling strategies.In this context,direct regeneration has emerged as a promising approach for reclaiming LFP cathode materials,offering a streamlined pathway to restore their electrochemical functionality.We report an integrated regeneration protocol that simultaneously repairs the degraded crystal structure and reconstructs the damaged carbon coating in spent LFP.The regenerated cathode material had superfast lithium-ion diffusion kinetics and a stable cathode-electrolyte interface,giving a remarkable rate capability with specific capacities of 122 m Ah g^(-1)at 5C and 106 m Ah g^(-1)at 10C(1C=170 m A g^(-1)).It also maintained capacities of 110.7 m Ah g^(-1)(5C)and 84.1 m Ah g^(-1)(10C)after 400 cycles.It could be used in harsh environments and could be stably cycled at subzero temperatures(-10 and-20°C)and in solid-state electrolyte batteries.Life cycle assessment combined with economic evaluation using the Ever Batt model reveals that this direct regeneration approach has high economic and environmental benefits.展开更多
Dual-carbon batteries(DCBs)have emerged as an appealing candidate for large-scale energy storage,yet the common trade-off between active sites and electronic conduction in carbon materials engenders a main challenge t...Dual-carbon batteries(DCBs)have emerged as an appealing candidate for large-scale energy storage,yet the common trade-off between active sites and electronic conduction in carbon materials engenders a main challenge towards efficient DCBs.Here,we introduce a heteroatom-doped sp^(3) /sp^(2) hybridized carbon fiber membrane(cPAN-Gr)as a universal binder-free active electrode that effectively overcomes this trade-off,enabling efficient Li-ion intercalation chemistry for advanced DCBs.By strategically tuning the sp^(3) and sp^(2) carbon hybridization,the interlayer interaction,geometric and electronic structures of c PANGr are simultaneously optimized,which facilitates rapid Li-ion adsorption,smooth interlayer transport,and efficient electron transport by maximizing the synergy between sp^(2) -and sp^(3) -hybridized carbon.This,coupled with a 3D porous network structure,endows the c PAN-Gr with superior Li-ion storage capability and fast reaction kinetics.Therefore,the c PAN-Gr electrode delivers a high reversible capacity of 345 m A h g^(-1),excellent rate capability(50 C),and an ultralong cycle life over 10,000 cycles,outperforming other reported carbon-based electrodes.Moreover,the constructed DCB exhibits a large specific capacity of 135 m A h g^(-1),long-term cyclability over 500 cycles,and a remarkable energy density of 524.4 Wh kg^(-1).The c PAN-Gr electrode can also be expanded to construct a LiFePO_(4)//cPAN-Gr full battery.Combined theoretical and experimental studies reveal the crucial role of an optimized sp^(3) /sp^(2) ratio(79%)with topological defects and pyridine/pyrrolic N sites on the performance enhancement.This work offers new insights into the design of advanced carbon materials for DCBs and beyond.展开更多
Na-ion batteries are considered a promising next-generation battery alternative to Li-ion batteries,due to the abundant Na resources and low cost.Most efforts focus on developing new materials to enhance energy densit...Na-ion batteries are considered a promising next-generation battery alternative to Li-ion batteries,due to the abundant Na resources and low cost.Most efforts focus on developing new materials to enhance energy density and electrochemical performance to enable it comparable to Li-ion batteries,without considering thermal hazard of Na-ion batteries and comparison with Li-ion batteries.To address this issue,our work comprehensively compares commercial prismatic lithium iron phosphate(LFP) battery,lithium nickel cobalt manganese oxide(NCM523) battery and Na-ion battery of the same size from thermal hazard perspective using Accelerating Rate Calorimeter.The thermal hazard of the three cells is then qualitatively assessed from thermal stability,early warning and thermal runaway severity perspectives by integrating eight characteristic parameters.The Na-ion cell displays comparable thermal stability with LFP while LFP exhibits the lowest thermal runaway hazard and severity.However,the Na-ion cell displays the lowest safety venting temperature and the longest time interval between safety venting and thermal runaway,allowing the generated gas to be released as early as possible and detected in a timely manner,providing sufficient time for early warning.Finally,a database of thermal runaway characteristic temperature for Li-ion and Na-ion cells is collected and processed to delineate four thermal hazard levels for quantitative assessment.Overall,LFP cells exhibit the lowest thermal hazard,followed by the Na-ion cells and NCM523 cells.This work clarifies the thermal hazard discrepancy between the Na-ion cell and prevalent Li-ion cells,providing crucial guidance for development and application of Na-ion cell.展开更多
With the widespread adoption of electric vehicles and energy storage systems,predicting the remaining useful life(RUL)of lithium-ion batteries(LIBs)is critical for enhancing system reliability and enabling predictive ...With the widespread adoption of electric vehicles and energy storage systems,predicting the remaining useful life(RUL)of lithium-ion batteries(LIBs)is critical for enhancing system reliability and enabling predictive maintenance.Traditional RUL prediction methods often exhibit reduced accuracy during the nonlinear aging stages of batteries and struggle to accommodate complex degradation processes.This paper introduces a novel adaptive long short-term memory(LSTM)approach that dynamically adjusts observation and prediction horizons to optimize predictive performance across various aging stages.The proposed method employs principal component analysis(PCA)for dimensionality reduction on publicly available NASA and Mendeley battery datasets to extract health indicators(HIs)and applies K-means clustering to segment the battery lifecycle into three aging stages(run-in,linear aging,and nonlinear aging),providing aging-stage-based input features for the model.Experimental results show that,in the NASA dataset,the adaptive LSTM reduces the MAE and RMSE by 0.042 and 0.043,respectively,compared to the CNN,demonstrating its effectiveness in mitigating error accumulation during the nonlinear aging stage.However,in the Mendeley dataset,the average prediction accuracy of the adaptive LSTM is slightly lower than that of the CNN and Transformer.These findings indicate that defining aging-stage-based adaptive observation and prediction horizons for LSTM can effectively enhance its performance in predicting battery RUL across the entire lifecycle.展开更多
The unique oxygen stacking sequence of O2-type structures restricts the irreversible transition metal movement into Li vacancies for the delithiated Li-rich layered oxides(LLOs)and maintains outstanding voltage stabil...The unique oxygen stacking sequence of O2-type structures restricts the irreversible transition metal movement into Li vacancies for the delithiated Li-rich layered oxides(LLOs)and maintains outstanding voltage stability.However,the ion-exchange synthesis promotes the Mn-ion valence reduction and aggravates the Jahn-Teller(J-T)distortion alongside disproportionation.Since the main oxidation state of the Mn ions is+4 in the traditional O3-type LLOs,synergistic effects of the O2-type and O3-type structures are expected in the O2/O3 diphasic Li-rich material.Herein,O2/O3 biphasic intergrowth LLOs were rationally designed,and the synergic optimization of the biphasic structure was planned to retard the J-T effect.The O2/O3 intergrowth nature was confirmed,and the percentages of the O2 and O3 phases were 56%and 44%,respectively.Density functional theory calculations demonstrated that the Mn^(2+)(EC)sheath had a remarkably lower energy barrier than the Li^(+)(EC)sheath.This finding suggests that Mn^(2+)ions that are dissolved into the electrolyte accelerate the electrolyte oxidization,so the deposition of the cathode electrolyte interface for pristine O2-LLOs causes a high electrochemical impedance.The designed O2/O3 biphasic LLOs boost the capacity stability and suppress the voltage drop upon repeated Li^(+)de-intercalation.The phase regulation strategy offers great potential for developing low-cost LLOs with enhanced structural stability for advanced Li-ion batteries.展开更多
In optimizing fast charge capability,mitigating side reaction rate,and unveiling particle cracking tolerance for Li-ion batteries(LIBs),the galvanostatic charge–discharge(GCD)at different charge/discharge rates,the s...In optimizing fast charge capability,mitigating side reaction rate,and unveiling particle cracking tolerance for Li-ion batteries(LIBs),the galvanostatic charge–discharge(GCD)at different charge/discharge rates,the static electrochemical impedance spectroscopy(SEIS)under open circuit voltage(OCV)conditions,and the dynamic EIS(DEIS)under dynamic conditions are widely used to investigate charge transfer reactions in LIBs.In spite of great progresses achieved,it is still an open question how to decouple charge transfer reactions under dynamic conditions,especially under conditions of different charge/discharge rates and state of charges(SOCs).To address the above challenges,this work develops a unified framework to digitize,visualize,and finally decouple charge transfer reactions in LIBs under dynamic conditions.In detail:(i)a set of matrix-based numerical solutions to GCD,SEIS,and DEIS are deduced for LIBs;(ii)an open-source DEIS-Toolbox@LIB to digitize/visualize charge transfer reactions is developed;(iii)EIS under dynamic and OCV conditions are discriminated;and(iv)a dynamic decoupling of charge transfer reactions is achieved with respect to core parameters under dynamic conditions for LIBs.The developed framework serves to digitize/visualize/decouple charge transfer reactions under dynamic conditions,and then to unveil limiting factors of fast charge/discharge and triggering mechanisms of side reactions for batteries.展开更多
Developing cost-effective single-crystalline Ni-rich Co-poor cathodes operating at high-voltage is one of the most important ways to achieve higher energy Li-ion batteries. However, the Li/O loss and Li/Ni mixing unde...Developing cost-effective single-crystalline Ni-rich Co-poor cathodes operating at high-voltage is one of the most important ways to achieve higher energy Li-ion batteries. However, the Li/O loss and Li/Ni mixing under high-temperature lithiation result in electrochemical kinetic hysteresis and structural instability. Herein, we report a highly-ordered single-crystalline LiNi0.85Co0.05Mn0.10O2(NCM85) cathode by doping K+and F-ions. To be specific, the K-ion as a fluxing agent can remarkably decrease the solid-state lithiation temperature by ~30°C, leading to less Li/Ni mixing and oxygen vacancy. Meanwhile, the strong transitional metal(TM)-F bonds are helpful for enhancing de-/lithiation kinetics and limiting the lattice oxygen escape even at 4.5 V high-voltage. Their advantages synergistically endow the single-crystalline NCM85 cathode with a very high reversible capacity of 222.3 mAh g-1. A superior capacity retention of 91.3% is obtained after 500 times at 1 C in pouch-type full cells, and a prediction value of 75.3% is given after cycling for 5000 h. These findings are reckoned to expedite the exploitation and application of high-voltage single-crystalline Ni-rich cathodes for next-generation Li-ion batteries.展开更多
The integration of photocatalysis with electrochemical energy storage offers promising solutions for offgrid power supply. Herein, carbon cloth-supported TiO_(2)nanorod arrays are engineered as a model platform to exp...The integration of photocatalysis with electrochemical energy storage offers promising solutions for offgrid power supply. Herein, carbon cloth-supported TiO_(2)nanorod arrays are engineered as a model platform to explore photoelectrochemical synergy in integrated photo-rechargeable lithium-ion batteries(PRLiBs). Through operando characterizations and theory calculations, we found that photoexcitation lowers the Li^(+)migration barrier by 0.16 eV through electronic states redistribution near the Fermi level,thereby accelerating Li^(+)transport and enhancing the intercalation process during photo-assisted charging and discharging. Three key principles governing dual operational modes(light-assisted charge/discharge and pure light charging) are established for PRLiBs:(i) the capacity enhancement during photoassisted charging is primarily due to photocatalytic Li^(+)extraction via hole-driven oxidation at the TiO_(2)/electrolyte interface and electric double-layer reconstruction;(ii) the long-standing controversy in solar-to-electricity conversion efficiency(g) is resolved by introducing a polarization-decoupled model to quantify g, distinguishing genuine catalytic contributions from parasitic self-charging effects;and(iii)during light-only charging without external bias, the capacity increase is predominantly driven by the photocatalytic oxidation of the TiO_(2)photoelectrode, a single-electrode process without electron transfer through an external circuit, distinct from conventional dual-electrode charging. This work lays a solid theoretical foundation for understanding the mechanisms of PRLiBs and provides precise guidelines for g calculations, offering valuable insights for the future development of photo-energy storage devices.展开更多
Strategic fluorination of solvent,a prominent strategy to enhance the electrolyte oxidation resistance and engineer a robust cathode-electrolyte interface,is crucial for realizing high-voltage lithium-ion batteries.Ac...Strategic fluorination of solvent,a prominent strategy to enhance the electrolyte oxidation resistance and engineer a robust cathode-electrolyte interface,is crucial for realizing high-voltage lithium-ion batteries.Actually,the adaptability of fluorinated solvents to high voltages is critically determined by the degree of fluorination and the fluorination site,yet lacks systematic design principles.Herein,we introduce a solvent screening descriptor based on ionization energy and Fukui function to assess molecular and site-specific reactivity.Computational and experimental results demonstrate that an optimal solvent with low ground-state energies and reactive sites is required as an ideal candidate for high-voltage electrolytes.Among derivatives from anisole,(trifluoromethoxy)benzene is identified as a superior candidate,enabling the formulation of a low reactivity solution(LPT)as electrolyte.Remarkably,the prepared Li‖LCO cell using LPT electrolyte maintained a high-capacity retention of 78.8%after 600 cycles at 4.5 V.In addition,the formation of an inorganic-rich interphase from LPT electrolyte effectively suppresses structural degradation to ensure a fast dynamic behavior.The utilization of LPT electrolyte also greatly reduces the amount of heat released and the production of O_(2)gas,which is favorable for addressing thermal runaway hazards.This screening strategy offers a practical approach for the design of flame-retardant high-voltage electrolytes.展开更多
Sulfide-based all-solid-state lithium metal batteries(ASSLMBs)have garnered significant attention due to their potential for high energy density and enhanced safety.However,their practical application is hindered by c...Sulfide-based all-solid-state lithium metal batteries(ASSLMBs)have garnered significant attention due to their potential for high energy density and enhanced safety.However,their practical application is hindered by challenges such as uneven lithium(Li)deposition and the growth of Li dendrites.In this contribution,we propose an amorphous fluorinated interphase(AFI),composed of amorphous LiF and lithiated graphite,to regulate the interfacial Li-ion transport kinetics through in-situ interface chemistry.Amorphous LiF,which exhibits a significantly enhanced Li-ion diffusion compared to its crystalline counterpart,works synergistically with lithiated graphite to promote both short-range and long-range Li-ion transport kinetics at the Li/electrolyte interface.As a result,the Li anode with AFI demonstrates a remarkably enhanced critical current density of 1.6 mA cm^(−2)and an extended cycle life exceeding 1100 h.The Li||LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)full cell also achieves a high discharge capacity of 125.7 mA h g^(−1)and retains 71.2%of its initial capacity after 200 cycles.This work provides valuable insights into the rational design of artificial anodic interphase to regulate interfacial Li-ion transport kinetics in ASSLMBs.展开更多
Increasing the charging cut-off voltage can significantly enhance the energy density of LiCoO_(2).However,the continuous deterioration of interface structure and transport kinetics under high voltage poses challenges ...Increasing the charging cut-off voltage can significantly enhance the energy density of LiCoO_(2).However,the continuous deterioration of interface structure and transport kinetics under high voltage poses challenges to electrochemical stability.This work proposes to in-situ construct a uniform element gradient modification structure on the surface and subsurface of LiCoO_(2).The modification structure contains an Sb_(2)O_(3)&SbF_(x)composite coating layer and an Sb-F doped spinel-like transition layer,simultaneously.The modified sample maintains an initial discharge specific capacity of 221.2 mA h g^(-1)and a capacity retention of 86%after 200 cycles at 3–4.6 V and 0.5 C.Moreover,it has a discharge specific capacity of163.3 mA h g^(-1)at a high rate of 5 C.Meanwhile,combining highly electronegative Sb^(3+)&F^(-)that widen the Li^(+)transport channel with the amorphous coating of F^(-)doped Sb_(2)O_(3)with higher conductivity improves the interface transport kinetics.This breaks the stereotypical view in traditional concepts that fluorinated coatings or inert metal oxide coatings inhibit Li^(+)transport.Moreover,the inert composite coating combined with Sb–O–F with high bond energy stabilizes the surface structure.A series of characterizations confirm that the joint improvement of interface structure stability and transport kinetics significantly enhances the electrochemical performance of LiCoO_(2).展开更多
It is of great importance to explore sustainable and eco-friendly recycling strategies for spent Li-ion batteries(LIBs).As such,the closed-loop resynthesis of LiNi_(x)CoyMn_(z)O_(2)(NCM)becomes recently popular as exe...It is of great importance to explore sustainable and eco-friendly recycling strategies for spent Li-ion batteries(LIBs).As such,the closed-loop resynthesis of LiNi_(x)CoyMn_(z)O_(2)(NCM)becomes recently popular as exemplified by the commercialization of low-and mid-Ni content NCM(33%-60%).However,there has been suspicion as to the successful deployment of Ni-rich NCM resynthesis process.Therefore,we systematically increase the Ni content of NCM from 60%to 90%from the industrial leachate of spent LIBs containing various metallic and nonmetallic impurities.The utilization rate of the leachate decreases from 71.8 mol%for NCM622 to 18.0 mol%for NCM955 as the Ni content in the NCM composition increases with the Co recycling rate being 100%in all resynthesized NCM(RNCM).The physicochemical and electrochemical properties of RNCM are systematically compared with its pristine NCM counterparts.As a result,various physicochemical properties of RNCM including impurity content,crystallographic information,morphology,particle size,porosity,specific surface area,elemental distribution,residual lithium compounds,and thermal stability are correlated with its electrochemical properties.It is found out that Al is the most critical impurity that determines the physicochemical and electrochemical properties of RNCM.It is noteworthy that RNCM955 prepared from spent LIBs without any purification step surpasses NCM955 in terms of rate and cycle performance.Further,this resynthesis approach toward Nirich NCM could meet the forthcoming 2031 EU's legislative target on the mandatory minimum recycling usage of valuable metals from spent LIBs.The anode active material was resynthesized using industrial leachate as the maximum.The amount of leachate used and the amount of impurities were proportional.展开更多
Tailoring 1D nanotubes with refined interfacial interactions and optimized adsorption sites presents a highly promising yet challenging strategy for advancing Na/Li-ion batteries(SIBs/LIBs).Herein,the intertwined yard...Tailoring 1D nanotubes with refined interfacial interactions and optimized adsorption sites presents a highly promising yet challenging strategy for advancing Na/Li-ion batteries(SIBs/LIBs).Herein,the intertwined yardlong bean-like Fe_(9)Ni_(9)S_(16)/FeS heterostructures with sulfur vacancies encapsulated in N-doped carbon nanotubes(3 N-Fe_(9)Ni_(9)S_(16)/FeS-3@CNTs)are controllably synthesized through Fe/Ni-catalyzed pyrolysis of dicyandiamide followed by sulfidation strategies.1D nanotubes with robust outer walls and internal cavity structures shorten the diffusion paths of ions/electrons and buffer volume expansion and aggregation of active materials.The Fe_(9)Ni_(9)S_(16)/FeS heterostructure provides a powerful driving force for charge transfer by forming built-in electric fields,optimizing ion adsorption,while the Fe_(9)Ni_(9)S_(16)features a wider interlayer spacing that allows for frequent Na+/Li+insertion and extraction,thereby enhancing the reaction kinetics within the electrode.Driven by these synergistic factors,the 3 N-Fe_(9)Ni_(9)S_(16)/FeS-3@CNTs demonstrates remarkable electrochemical performance,achieving a substantial reversible capacity of up to 682.1mA h g^(−1)for SIBs at 0.1 A g^(−1)and 782.7 mA h g^(−1)for LIBs at 0.5 A g−1,alongside exceptional cycling stability in SIBs,maintaining 78.7%of its capacity after 1500 cycles at 1 A g^(−1)coupling with the ether-based electrolyte.Employing various electrochemical analyses in conjunction with ex-situ characterization techniques and Density Functional Theory(DFT)calculations,the storage mechanisms and phase transition processes are investigated,elucidating the structure-composition-performance relationships.This work paves the way for a new strategy in designing advanced materials with engineered heterostructures and controllable defects for energy conversion and storage devices.展开更多
A design for a Li-ion battery charger IC that can operate in a constant current-constant voltage （CC- CV） charge mode is proposed. In the CC-CV charge mode,the charger IC provides a constant charging current at the ...A design for a Li-ion battery charger IC that can operate in a constant current-constant voltage （CC- CV） charge mode is proposed. In the CC-CV charge mode,the charger IC provides a constant charging current at the beginning, and then the charging current begins to decrease before the battery voltage reaches its final value. After the battery voltage reaches its final value and remains constant,the charging current is further reduced. This approach prevents charging the battery with full current near its saturated voltage,which can cause heating. The novel design of the core of the charger IC realizes the proposed CC-CV charge mode. The chip was implemented in a CSMC 0.6μm CMOS mixed signal process. The experimental results verify the realization of the proposed CC- CV charge mode. The voltage of the battery after charging is 4. 1833V.展开更多
The physics of ionic and electrical conduction at electrode materials of lithium-ion batteries （LIBs） are briefly sum marized here, besides, we review the current research on ionic and electrical conduction in elect...The physics of ionic and electrical conduction at electrode materials of lithium-ion batteries （LIBs） are briefly sum marized here, besides, we review the current research on ionic and electrical conduction in electrode material incorporating experimental and simulation studies. Commercial LIBs have been widely used in portable electronic devices and are now developed for large-scale applications in hybrid electric vehicles （HEV） and stationary distributed power stations. However, due to the physical limits of the materials, the overall performance of today＇s LIBs does not meet all the requirements for future applications, and the transport problem has been one of the main barriers to further improvement. The electron and Li-ion transport behaviors are important in determining the rate capacity of LIBs.展开更多
Modification of LiFePO4, LiMn2O4 and Li1＋xV3O8 by doping yttrium was investigated. The influences of doping Y on structure, morphology and electrochemical performance of cathode materials were investigated systematic...Modification of LiFePO4, LiMn2O4 and Li1＋xV3O8 by doping yttrium was investigated. The influences of doping Y on structure, morphology and electrochemical performance of cathode materials were investigated systematically. The results indicated that the mechanisms of Y doping in three cathode materials were different, so the influences on the material performance were different. The crystal structure of the three materials was not changed by Y doping. However, the crystal parameters were influenced. The crystal parameters of LiMn2O4 became smaller, and the interlayer distance of （100） crystal plane of Li1-xV3O8 was lengthened after Y doping. The grain size of Y-doped LiFePO4 became smaller and grain morphology became more regular than that of undoped LiFePO4. It indicated that Y doping had no influence on crystal particle and morphology of LiMn2O4. The morphology of Li1＋xV3O8 became irregular and its size became larger with the increase of Y. For LiFePOaand Li1＋xV3O8, both the initial discharge capacities and the cyclic performance were improved by Y doping. For LiMn2O4, the cyclic performance became better and the initial discharge capacities declined with increasing Y doping.展开更多
Si has been considered as one of the most attractive anode materials for Li-ion batteries(LIBs) because of its high gravimetric and volumetric capacity. Importantly, it is also abundant, cheap, and environmentally ben...Si has been considered as one of the most attractive anode materials for Li-ion batteries(LIBs) because of its high gravimetric and volumetric capacity. Importantly, it is also abundant, cheap, and environmentally benign. In this review, we summarized the recent progress in developments of Si anode materials. First, the electrochemical reaction and failure are outlined, and then, we summarized various methods for improving the battery performance, including those of nanostructuring, alloying, forming hierarchic structures, and using suitable binders. We hope that this review can be of benefit to more intensive investigation of Si-based anode materials.展开更多
Carbon nanotubes (CNTs) and acetylene black (AB) were dispersed synchronously or separately between LiFePO4 (LFP) particles as conducting agents during the course of manufacture of LiFePO4 cathodes. The morphology and...Carbon nanotubes (CNTs) and acetylene black (AB) were dispersed synchronously or separately between LiFePO4 (LFP) particles as conducting agents during the course of manufacture of LiFePO4 cathodes. The morphology and electrochemical performances of as-prepared LiFePO4 were evaluated by means of transmission electron microscopy (TEM), charge-discharge test, electrochemical impedance spectroscope (EIS) and cyclic voltammetry (CV). CNTs contribute to the interconnection of the isolated LiFePO4 or carbon particles. For the CNTs-modified LiFePO4, it exhibits excellent performance in terms of both specific capacity and cycle life. The initial discharge capacity is 147.9 mA·h/g at 0.2C rate and 134.2 mA·h/g at 1C rate, keeping a capacity retention ratio of 97% after 50 cycles. The results from EIS indicate that the impedance value of the solid electrolyte interface decreases. The cyclic voltammetric peak profiles is more symmetric and spiculate and there are fewer peaks. CNTs are promising conductive additives candidate for high-power Li-ion batteries.展开更多
基金support from Guangdong Basic and Applied Basic Research Foundation(2020B1515420001 and 2023B1515040027)Fundamental Research Funds for the Central Universities,Sun Yat-sen University(23yxqntd002)the Postdoctoral Fellowship Program of CPSF(GZC20242066).
文摘Redox-active covalent organic polymers(COPs)have emerged as appealing renewable electrode materials for next-generation Li-ion batteries,but their performance is limited by insufficient redox sites and inadequate Li-ion diffusion.Here,we develop a novel class of mesoporous covalent organic polymer(namely TF-Azo-COP)bearing multiple redox sites and explore its first use as efficient 18-electron-redox anodes for superior Li-ion storage in both coin-type and fiber-type batteries.The newly produced TF-Azo-COP involves three types of active sites including C=N in triazines and imines,N=N in azo,and C6-ring aromatics to enable 18-Li-ion storage on one repeatable segment,while affording extendedπ-conjugation for fast electron transfer and a pore size of~2.5 nm for facilitated ion diffusion with a high coefficient up to~10^(-10)cm^(2)s^(-1)—superior to some reported organic electrodes.Meriting from the above,pairing TF-Azo-COP with metal Li endows a coin cell with good cycling stability and a large reversible capacity of 795.4 mAh g^(-1)at 0.1 A g^(-1)—representing one of the best performances among reported organic electrodes.When coupled with fiber-shaped LiFePO_(4)cathodes,the assembled fiber cell delivers an excellent combination of linear capacity(0.23 mAh cm^(-1)),energy density(0.55 mWh cm^(-1)),cycling stability(250 cycles),and good flexibility.
基金supported by the National Natural Science Foundation of China(Nos.22479092 and 22078190)。
文摘The pseudo-two-dimensional(P2D)model plays an important role in exploring physicochemical mechanisms,predicting the state of health,and improving the fast charge capability for Li-ion batteries(LIBs).However,the fast charge leads to the lithium concentration gradient in the solid and electrolyte phases and the non-uniform electrochemical reaction at the solid/electrolyte interface.In order to decouple charge transfer reactions in LIBs under dynamic conditions,understanding the spatio-temporal resolution of the P2D model is urgently required.Till now,the study of this aspect is still insufficient.This work studies the spatio-temporal resolution for dynamic/static electrochemical impedance spectroscopy(DEIS/SEIS)on multiple scales.In detail,DEIS and SEIS with spatio-temporal resolutions are used to decouple charge transfer reactions in LIBs based on the numerical solution of the P2D model in the frequency domain.The calculated results indicate that decoupling solid diffusion requires a high spatial resolution along the r-direction in particles,decoupling electrolyte diffusion and interfacial transfer reaction requires a high spatial resolution along the x-direction,and decoupling charge transfer reactions in LIBs at an extremely low state of charge(SOC)requires an extremely high temporal resolution along the t-direction.Finally,the optimal range of spatio-temporal resolutions for DEIS/SEIS is derived,and the method to decouple charge transfer reactions with spatio-temporal resolutions is developed.
基金financial support from the National Key R&D Program of China(2022YFB2402600)the National Natural Science Foundation of China(52372250,52125105,52173242)+1 种基金Shenzhen Science and Technology Planning Project(RCYX20221008092850072,JSGG20220831104004008,KJZD20230923113859006,JCYJ20220531100405012,KJZD20241122161900001)Science and Technology Planning Project of Guangdong Province(2024A1515030076)。
文摘The rapid accumulation of spent LiFePO_(4)(LFP)cathodes from retired lithium-ion batteries necessitates the development of effective and environmental-friendly recycling strategies.In this context,direct regeneration has emerged as a promising approach for reclaiming LFP cathode materials,offering a streamlined pathway to restore their electrochemical functionality.We report an integrated regeneration protocol that simultaneously repairs the degraded crystal structure and reconstructs the damaged carbon coating in spent LFP.The regenerated cathode material had superfast lithium-ion diffusion kinetics and a stable cathode-electrolyte interface,giving a remarkable rate capability with specific capacities of 122 m Ah g^(-1)at 5C and 106 m Ah g^(-1)at 10C(1C=170 m A g^(-1)).It also maintained capacities of 110.7 m Ah g^(-1)(5C)and 84.1 m Ah g^(-1)(10C)after 400 cycles.It could be used in harsh environments and could be stably cycled at subzero temperatures(-10 and-20°C)and in solid-state electrolyte batteries.Life cycle assessment combined with economic evaluation using the Ever Batt model reveals that this direct regeneration approach has high economic and environmental benefits.
基金financial support from Guangdong Basic and Applied Basic Research Foundation(2020B1515420001and 2023B1515040027)Fundamental Research Funds for the Central Universities,Sun Yat-sen University(23yxqntd002)the Postdoctoral Fellowship Program of CPSF(GZC20242066)。
文摘Dual-carbon batteries(DCBs)have emerged as an appealing candidate for large-scale energy storage,yet the common trade-off between active sites and electronic conduction in carbon materials engenders a main challenge towards efficient DCBs.Here,we introduce a heteroatom-doped sp^(3) /sp^(2) hybridized carbon fiber membrane(cPAN-Gr)as a universal binder-free active electrode that effectively overcomes this trade-off,enabling efficient Li-ion intercalation chemistry for advanced DCBs.By strategically tuning the sp^(3) and sp^(2) carbon hybridization,the interlayer interaction,geometric and electronic structures of c PANGr are simultaneously optimized,which facilitates rapid Li-ion adsorption,smooth interlayer transport,and efficient electron transport by maximizing the synergy between sp^(2) -and sp^(3) -hybridized carbon.This,coupled with a 3D porous network structure,endows the c PAN-Gr with superior Li-ion storage capability and fast reaction kinetics.Therefore,the c PAN-Gr electrode delivers a high reversible capacity of 345 m A h g^(-1),excellent rate capability(50 C),and an ultralong cycle life over 10,000 cycles,outperforming other reported carbon-based electrodes.Moreover,the constructed DCB exhibits a large specific capacity of 135 m A h g^(-1),long-term cyclability over 500 cycles,and a remarkable energy density of 524.4 Wh kg^(-1).The c PAN-Gr electrode can also be expanded to construct a LiFePO_(4)//cPAN-Gr full battery.Combined theoretical and experimental studies reveal the crucial role of an optimized sp^(3) /sp^(2) ratio(79%)with topological defects and pyridine/pyrrolic N sites on the performance enhancement.This work offers new insights into the design of advanced carbon materials for DCBs and beyond.
基金supported by the National Key R&D Program of China(No.2022YFE0207400)supported by the Xiaomi Young Talents Programsupported by the Youth Innovation Promotion Association CAS(No.Y201768)。
文摘Na-ion batteries are considered a promising next-generation battery alternative to Li-ion batteries,due to the abundant Na resources and low cost.Most efforts focus on developing new materials to enhance energy density and electrochemical performance to enable it comparable to Li-ion batteries,without considering thermal hazard of Na-ion batteries and comparison with Li-ion batteries.To address this issue,our work comprehensively compares commercial prismatic lithium iron phosphate(LFP) battery,lithium nickel cobalt manganese oxide(NCM523) battery and Na-ion battery of the same size from thermal hazard perspective using Accelerating Rate Calorimeter.The thermal hazard of the three cells is then qualitatively assessed from thermal stability,early warning and thermal runaway severity perspectives by integrating eight characteristic parameters.The Na-ion cell displays comparable thermal stability with LFP while LFP exhibits the lowest thermal runaway hazard and severity.However,the Na-ion cell displays the lowest safety venting temperature and the longest time interval between safety venting and thermal runaway,allowing the generated gas to be released as early as possible and detected in a timely manner,providing sufficient time for early warning.Finally,a database of thermal runaway characteristic temperature for Li-ion and Na-ion cells is collected and processed to delineate four thermal hazard levels for quantitative assessment.Overall,LFP cells exhibit the lowest thermal hazard,followed by the Na-ion cells and NCM523 cells.This work clarifies the thermal hazard discrepancy between the Na-ion cell and prevalent Li-ion cells,providing crucial guidance for development and application of Na-ion cell.
基金supported by National Natural Science Foundation of China(Grant No.62403475).
文摘With the widespread adoption of electric vehicles and energy storage systems,predicting the remaining useful life(RUL)of lithium-ion batteries(LIBs)is critical for enhancing system reliability and enabling predictive maintenance.Traditional RUL prediction methods often exhibit reduced accuracy during the nonlinear aging stages of batteries and struggle to accommodate complex degradation processes.This paper introduces a novel adaptive long short-term memory(LSTM)approach that dynamically adjusts observation and prediction horizons to optimize predictive performance across various aging stages.The proposed method employs principal component analysis(PCA)for dimensionality reduction on publicly available NASA and Mendeley battery datasets to extract health indicators(HIs)and applies K-means clustering to segment the battery lifecycle into three aging stages(run-in,linear aging,and nonlinear aging),providing aging-stage-based input features for the model.Experimental results show that,in the NASA dataset,the adaptive LSTM reduces the MAE and RMSE by 0.042 and 0.043,respectively,compared to the CNN,demonstrating its effectiveness in mitigating error accumulation during the nonlinear aging stage.However,in the Mendeley dataset,the average prediction accuracy of the adaptive LSTM is slightly lower than that of the CNN and Transformer.These findings indicate that defining aging-stage-based adaptive observation and prediction horizons for LSTM can effectively enhance its performance in predicting battery RUL across the entire lifecycle.
基金supported by the National Natural Science Foundation of China(Nos.22379052,22479062 and 52102252)Taishan Scholars of Shandong Province(No.tsqnz20221143)Independent Cultivation Program of Innovation Team of Ji’nan City(No.202333042).
文摘The unique oxygen stacking sequence of O2-type structures restricts the irreversible transition metal movement into Li vacancies for the delithiated Li-rich layered oxides(LLOs)and maintains outstanding voltage stability.However,the ion-exchange synthesis promotes the Mn-ion valence reduction and aggravates the Jahn-Teller(J-T)distortion alongside disproportionation.Since the main oxidation state of the Mn ions is+4 in the traditional O3-type LLOs,synergistic effects of the O2-type and O3-type structures are expected in the O2/O3 diphasic Li-rich material.Herein,O2/O3 biphasic intergrowth LLOs were rationally designed,and the synergic optimization of the biphasic structure was planned to retard the J-T effect.The O2/O3 intergrowth nature was confirmed,and the percentages of the O2 and O3 phases were 56%and 44%,respectively.Density functional theory calculations demonstrated that the Mn^(2+)(EC)sheath had a remarkably lower energy barrier than the Li^(+)(EC)sheath.This finding suggests that Mn^(2+)ions that are dissolved into the electrolyte accelerate the electrolyte oxidization,so the deposition of the cathode electrolyte interface for pristine O2-LLOs causes a high electrochemical impedance.The designed O2/O3 biphasic LLOs boost the capacity stability and suppress the voltage drop upon repeated Li^(+)de-intercalation.The phase regulation strategy offers great potential for developing low-cost LLOs with enhanced structural stability for advanced Li-ion batteries.
基金supported by the National Natural Science Foundation of China(22479092,22078190)。
文摘In optimizing fast charge capability,mitigating side reaction rate,and unveiling particle cracking tolerance for Li-ion batteries(LIBs),the galvanostatic charge–discharge(GCD)at different charge/discharge rates,the static electrochemical impedance spectroscopy(SEIS)under open circuit voltage(OCV)conditions,and the dynamic EIS(DEIS)under dynamic conditions are widely used to investigate charge transfer reactions in LIBs.In spite of great progresses achieved,it is still an open question how to decouple charge transfer reactions under dynamic conditions,especially under conditions of different charge/discharge rates and state of charges(SOCs).To address the above challenges,this work develops a unified framework to digitize,visualize,and finally decouple charge transfer reactions in LIBs under dynamic conditions.In detail:(i)a set of matrix-based numerical solutions to GCD,SEIS,and DEIS are deduced for LIBs;(ii)an open-source DEIS-Toolbox@LIB to digitize/visualize charge transfer reactions is developed;(iii)EIS under dynamic and OCV conditions are discriminated;and(iv)a dynamic decoupling of charge transfer reactions is achieved with respect to core parameters under dynamic conditions for LIBs.The developed framework serves to digitize/visualize/decouple charge transfer reactions under dynamic conditions,and then to unveil limiting factors of fast charge/discharge and triggering mechanisms of side reactions for batteries.
基金supported by the National Natural Science Foundation of China(U22A20429 and 22308103)Shanghai Pilot Program for Basic Research(22TQ1400100-13)+2 种基金Postdoctoral Fellowship Program of CPSF(GZB20230214)China Postdoctoral Science Foundation(2023M731083)the Fundamental Research Funds for the Central Universities.
文摘Developing cost-effective single-crystalline Ni-rich Co-poor cathodes operating at high-voltage is one of the most important ways to achieve higher energy Li-ion batteries. However, the Li/O loss and Li/Ni mixing under high-temperature lithiation result in electrochemical kinetic hysteresis and structural instability. Herein, we report a highly-ordered single-crystalline LiNi0.85Co0.05Mn0.10O2(NCM85) cathode by doping K+and F-ions. To be specific, the K-ion as a fluxing agent can remarkably decrease the solid-state lithiation temperature by ~30°C, leading to less Li/Ni mixing and oxygen vacancy. Meanwhile, the strong transitional metal(TM)-F bonds are helpful for enhancing de-/lithiation kinetics and limiting the lattice oxygen escape even at 4.5 V high-voltage. Their advantages synergistically endow the single-crystalline NCM85 cathode with a very high reversible capacity of 222.3 mAh g-1. A superior capacity retention of 91.3% is obtained after 500 times at 1 C in pouch-type full cells, and a prediction value of 75.3% is given after cycling for 5000 h. These findings are reckoned to expedite the exploitation and application of high-voltage single-crystalline Ni-rich cathodes for next-generation Li-ion batteries.
基金the financial support from the National Natural Science Foundation of China (22472040)the Basic and Applied Basic Research Foundation of Guangdong Province (2023A1515012033)。
文摘The integration of photocatalysis with electrochemical energy storage offers promising solutions for offgrid power supply. Herein, carbon cloth-supported TiO_(2)nanorod arrays are engineered as a model platform to explore photoelectrochemical synergy in integrated photo-rechargeable lithium-ion batteries(PRLiBs). Through operando characterizations and theory calculations, we found that photoexcitation lowers the Li^(+)migration barrier by 0.16 eV through electronic states redistribution near the Fermi level,thereby accelerating Li^(+)transport and enhancing the intercalation process during photo-assisted charging and discharging. Three key principles governing dual operational modes(light-assisted charge/discharge and pure light charging) are established for PRLiBs:(i) the capacity enhancement during photoassisted charging is primarily due to photocatalytic Li^(+)extraction via hole-driven oxidation at the TiO_(2)/electrolyte interface and electric double-layer reconstruction;(ii) the long-standing controversy in solar-to-electricity conversion efficiency(g) is resolved by introducing a polarization-decoupled model to quantify g, distinguishing genuine catalytic contributions from parasitic self-charging effects;and(iii)during light-only charging without external bias, the capacity increase is predominantly driven by the photocatalytic oxidation of the TiO_(2)photoelectrode, a single-electrode process without electron transfer through an external circuit, distinct from conventional dual-electrode charging. This work lays a solid theoretical foundation for understanding the mechanisms of PRLiBs and provides precise guidelines for g calculations, offering valuable insights for the future development of photo-energy storage devices.
基金financial support from the National Natural Science Foundation of China(22522814,22278378,and 52402318)Zhejiang Provincial Natural Science Foundation of China(LDQ24E030001 and LQN25E020003)Science Foundation of Zhejiang Sci-Tech University(22212011-Y and 24212149-Y).
文摘Strategic fluorination of solvent,a prominent strategy to enhance the electrolyte oxidation resistance and engineer a robust cathode-electrolyte interface,is crucial for realizing high-voltage lithium-ion batteries.Actually,the adaptability of fluorinated solvents to high voltages is critically determined by the degree of fluorination and the fluorination site,yet lacks systematic design principles.Herein,we introduce a solvent screening descriptor based on ionization energy and Fukui function to assess molecular and site-specific reactivity.Computational and experimental results demonstrate that an optimal solvent with low ground-state energies and reactive sites is required as an ideal candidate for high-voltage electrolytes.Among derivatives from anisole,(trifluoromethoxy)benzene is identified as a superior candidate,enabling the formulation of a low reactivity solution(LPT)as electrolyte.Remarkably,the prepared Li‖LCO cell using LPT electrolyte maintained a high-capacity retention of 78.8%after 600 cycles at 4.5 V.In addition,the formation of an inorganic-rich interphase from LPT electrolyte effectively suppresses structural degradation to ensure a fast dynamic behavior.The utilization of LPT electrolyte also greatly reduces the amount of heat released and the production of O_(2)gas,which is favorable for addressing thermal runaway hazards.This screening strategy offers a practical approach for the design of flame-retardant high-voltage electrolytes.
基金supported by the Beijing Municipal Natural Science Foundation(L223009)the National Natural Science Foundation of China(22209014,22479012)+1 种基金the Hebei Natural Science Foundation(E2024208084)the Fundamental Research Funds for the Central Universities(2023CX01031)。
文摘Sulfide-based all-solid-state lithium metal batteries(ASSLMBs)have garnered significant attention due to their potential for high energy density and enhanced safety.However,their practical application is hindered by challenges such as uneven lithium(Li)deposition and the growth of Li dendrites.In this contribution,we propose an amorphous fluorinated interphase(AFI),composed of amorphous LiF and lithiated graphite,to regulate the interfacial Li-ion transport kinetics through in-situ interface chemistry.Amorphous LiF,which exhibits a significantly enhanced Li-ion diffusion compared to its crystalline counterpart,works synergistically with lithiated graphite to promote both short-range and long-range Li-ion transport kinetics at the Li/electrolyte interface.As a result,the Li anode with AFI demonstrates a remarkably enhanced critical current density of 1.6 mA cm^(−2)and an extended cycle life exceeding 1100 h.The Li||LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)full cell also achieves a high discharge capacity of 125.7 mA h g^(−1)and retains 71.2%of its initial capacity after 200 cycles.This work provides valuable insights into the rational design of artificial anodic interphase to regulate interfacial Li-ion transport kinetics in ASSLMBs.
基金supported by the National Natural Science Foundation of China(22075170)employed resources from the BL11B station of the Shanghai Synchrotron Radiation Facility(SSRF,under contract number:2023-SSRF-PT-502681)。
文摘Increasing the charging cut-off voltage can significantly enhance the energy density of LiCoO_(2).However,the continuous deterioration of interface structure and transport kinetics under high voltage poses challenges to electrochemical stability.This work proposes to in-situ construct a uniform element gradient modification structure on the surface and subsurface of LiCoO_(2).The modification structure contains an Sb_(2)O_(3)&SbF_(x)composite coating layer and an Sb-F doped spinel-like transition layer,simultaneously.The modified sample maintains an initial discharge specific capacity of 221.2 mA h g^(-1)and a capacity retention of 86%after 200 cycles at 3–4.6 V and 0.5 C.Moreover,it has a discharge specific capacity of163.3 mA h g^(-1)at a high rate of 5 C.Meanwhile,combining highly electronegative Sb^(3+)&F^(-)that widen the Li^(+)transport channel with the amorphous coating of F^(-)doped Sb_(2)O_(3)with higher conductivity improves the interface transport kinetics.This breaks the stereotypical view in traditional concepts that fluorinated coatings or inert metal oxide coatings inhibit Li^(+)transport.Moreover,the inert composite coating combined with Sb–O–F with high bond energy stabilizes the surface structure.A series of characterizations confirm that the joint improvement of interface structure stability and transport kinetics significantly enhances the electrochemical performance of LiCoO_(2).
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(RS-2023-00254424)by the ITRC(Information Technology Research Center)support program(IITP-2024-RS-2024-00437494)supervised by the IITP(Institute for Information&Communications Technology Planning&Evaluation)funded by the MSIT(Ministry of Science and ICT),Korea。
文摘It is of great importance to explore sustainable and eco-friendly recycling strategies for spent Li-ion batteries(LIBs).As such,the closed-loop resynthesis of LiNi_(x)CoyMn_(z)O_(2)(NCM)becomes recently popular as exemplified by the commercialization of low-and mid-Ni content NCM(33%-60%).However,there has been suspicion as to the successful deployment of Ni-rich NCM resynthesis process.Therefore,we systematically increase the Ni content of NCM from 60%to 90%from the industrial leachate of spent LIBs containing various metallic and nonmetallic impurities.The utilization rate of the leachate decreases from 71.8 mol%for NCM622 to 18.0 mol%for NCM955 as the Ni content in the NCM composition increases with the Co recycling rate being 100%in all resynthesized NCM(RNCM).The physicochemical and electrochemical properties of RNCM are systematically compared with its pristine NCM counterparts.As a result,various physicochemical properties of RNCM including impurity content,crystallographic information,morphology,particle size,porosity,specific surface area,elemental distribution,residual lithium compounds,and thermal stability are correlated with its electrochemical properties.It is found out that Al is the most critical impurity that determines the physicochemical and electrochemical properties of RNCM.It is noteworthy that RNCM955 prepared from spent LIBs without any purification step surpasses NCM955 in terms of rate and cycle performance.Further,this resynthesis approach toward Nirich NCM could meet the forthcoming 2031 EU's legislative target on the mandatory minimum recycling usage of valuable metals from spent LIBs.The anode active material was resynthesized using industrial leachate as the maximum.The amount of leachate used and the amount of impurities were proportional.
基金supported by the program of National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT and Future planning(grant number 2022R1A4A1034312,2023R1A2C1007413)by the Commercialization Promotion Agency for R&D Outcomes(COMPA)grant funded by the Korean Government(Ministery of Science and ICT)(RS-2023-00304764)。
文摘Tailoring 1D nanotubes with refined interfacial interactions and optimized adsorption sites presents a highly promising yet challenging strategy for advancing Na/Li-ion batteries(SIBs/LIBs).Herein,the intertwined yardlong bean-like Fe_(9)Ni_(9)S_(16)/FeS heterostructures with sulfur vacancies encapsulated in N-doped carbon nanotubes(3 N-Fe_(9)Ni_(9)S_(16)/FeS-3@CNTs)are controllably synthesized through Fe/Ni-catalyzed pyrolysis of dicyandiamide followed by sulfidation strategies.1D nanotubes with robust outer walls and internal cavity structures shorten the diffusion paths of ions/electrons and buffer volume expansion and aggregation of active materials.The Fe_(9)Ni_(9)S_(16)/FeS heterostructure provides a powerful driving force for charge transfer by forming built-in electric fields,optimizing ion adsorption,while the Fe_(9)Ni_(9)S_(16)features a wider interlayer spacing that allows for frequent Na+/Li+insertion and extraction,thereby enhancing the reaction kinetics within the electrode.Driven by these synergistic factors,the 3 N-Fe_(9)Ni_(9)S_(16)/FeS-3@CNTs demonstrates remarkable electrochemical performance,achieving a substantial reversible capacity of up to 682.1mA h g^(−1)for SIBs at 0.1 A g^(−1)and 782.7 mA h g^(−1)for LIBs at 0.5 A g−1,alongside exceptional cycling stability in SIBs,maintaining 78.7%of its capacity after 1500 cycles at 1 A g^(−1)coupling with the ether-based electrolyte.Employing various electrochemical analyses in conjunction with ex-situ characterization techniques and Density Functional Theory(DFT)calculations,the storage mechanisms and phase transition processes are investigated,elucidating the structure-composition-performance relationships.This work paves the way for a new strategy in designing advanced materials with engineered heterostructures and controllable defects for energy conversion and storage devices.
文摘A design for a Li-ion battery charger IC that can operate in a constant current-constant voltage （CC- CV） charge mode is proposed. In the CC-CV charge mode,the charger IC provides a constant charging current at the beginning, and then the charging current begins to decrease before the battery voltage reaches its final value. After the battery voltage reaches its final value and remains constant,the charging current is further reduced. This approach prevents charging the battery with full current near its saturated voltage,which can cause heating. The novel design of the core of the charger IC realizes the proposed CC-CV charge mode. The chip was implemented in a CSMC 0.6μm CMOS mixed signal process. The experimental results verify the realization of the proposed CC- CV charge mode. The voltage of the battery after charging is 4. 1833V.
基金supported by the National High Technology Research and Development Program of China(Grant No.2015AA034201)the National Natural Science Foundation of China(Grant Nos.11234013 and 11264014)+2 种基金the Natural Science Foundation of Jiangxi Province,China(Grant Nos.20133ACB21010 and20142BAB212002)the Foundation of Jiangxi Education Committee,China(Grant Nos.GJJ14254 and KJLD14024)supported by the"Gan-po talent 555"Project of Jiangxi Province,China
文摘The physics of ionic and electrical conduction at electrode materials of lithium-ion batteries （LIBs） are briefly sum marized here, besides, we review the current research on ionic and electrical conduction in electrode material incorporating experimental and simulation studies. Commercial LIBs have been widely used in portable electronic devices and are now developed for large-scale applications in hybrid electric vehicles （HEV） and stationary distributed power stations. However, due to the physical limits of the materials, the overall performance of today＇s LIBs does not meet all the requirements for future applications, and the transport problem has been one of the main barriers to further improvement. The electron and Li-ion transport behaviors are important in determining the rate capacity of LIBs.
文摘Modification of LiFePO4, LiMn2O4 and Li1＋xV3O8 by doping yttrium was investigated. The influences of doping Y on structure, morphology and electrochemical performance of cathode materials were investigated systematically. The results indicated that the mechanisms of Y doping in three cathode materials were different, so the influences on the material performance were different. The crystal structure of the three materials was not changed by Y doping. However, the crystal parameters were influenced. The crystal parameters of LiMn2O4 became smaller, and the interlayer distance of （100） crystal plane of Li1-xV3O8 was lengthened after Y doping. The grain size of Y-doped LiFePO4 became smaller and grain morphology became more regular than that of undoped LiFePO4. It indicated that Y doping had no influence on crystal particle and morphology of LiMn2O4. The morphology of Li1＋xV3O8 became irregular and its size became larger with the increase of Y. For LiFePOaand Li1＋xV3O8, both the initial discharge capacities and the cyclic performance were improved by Y doping. For LiMn2O4, the cyclic performance became better and the initial discharge capacities declined with increasing Y doping.
基金partially supported by Beijing High-level Oversea Talent Projectthe strategic research grant ‘‘Laser interference process of silver nanostructures for surface enhanced Raman spectroscopy and environment application’’ (KZ201410005001) of Beijing Nature Science Foundation, the P. R. China
文摘Si has been considered as one of the most attractive anode materials for Li-ion batteries(LIBs) because of its high gravimetric and volumetric capacity. Importantly, it is also abundant, cheap, and environmentally benign. In this review, we summarized the recent progress in developments of Si anode materials. First, the electrochemical reaction and failure are outlined, and then, we summarized various methods for improving the battery performance, including those of nanostructuring, alloying, forming hierarchic structures, and using suitable binders. We hope that this review can be of benefit to more intensive investigation of Si-based anode materials.
基金Project(06B002)supported by Scientific Research Fund of Hunan Provincial Education Department of ChinaProject(09JJ3092)supported by Hunan Provincial Natural Science Foundation of ChinaProject(2008FJ3008)supported by the Planned Science and Technology Project of Hunan Province of China
文摘Carbon nanotubes (CNTs) and acetylene black (AB) were dispersed synchronously or separately between LiFePO4 (LFP) particles as conducting agents during the course of manufacture of LiFePO4 cathodes. The morphology and electrochemical performances of as-prepared LiFePO4 were evaluated by means of transmission electron microscopy (TEM), charge-discharge test, electrochemical impedance spectroscope (EIS) and cyclic voltammetry (CV). CNTs contribute to the interconnection of the isolated LiFePO4 or carbon particles. For the CNTs-modified LiFePO4, it exhibits excellent performance in terms of both specific capacity and cycle life. The initial discharge capacity is 147.9 mA·h/g at 0.2C rate and 134.2 mA·h/g at 1C rate, keeping a capacity retention ratio of 97% after 50 cycles. The results from EIS indicate that the impedance value of the solid electrolyte interface decreases. The cyclic voltammetric peak profiles is more symmetric and spiculate and there are fewer peaks. CNTs are promising conductive additives candidate for high-power Li-ion batteries.
